(1) Field of the Invention
The present invention relates to a low cost electroconductive spring material excellent in electroconductivity and spring performance, which is used as a material for electric devices such as a connector, a switch, a relay and the like.
(2) Related Art Statement
As the electroconductive spring materials having excellent electroconductivity and spring performance, there are typically specified as C-5191 or C-5212 in JIS (Japanese Industrial Standard), H3110 and C-5210 in JIS H3130 for instance phosphor bronze containing from 5.5 to 9.0% by weight (hereinafter referred to briefly as "%" throughout the specification) of Sn and from 0.03 to 0.35% of P. Since the electroconductivity, bending formability, stress relaxation property and the like are insufficient when such phosphor bronze is used in miniaturized electronic parts, with the high reliability required, there has been increasing demand for improvements thereof. On the other hand, as one of the electroconductive spring materials meeting such demand, there is an alloy with a nominal composition of 0.4% of Be, 1.8% of Ni and the balance being Cu (Cu-0.4% Be-1.8% Ni). However, the material cost is unfavorably high because of a high price of Be (For instance, Japanese Patent Application Laid-open No. 14,612/1978).
The present invention has been accomplished to solve the problems encountered by the prior art alloys.